The use of red blood cell (RBC) concentrates for providing oxygen carrying capacity in transfusion medicine is well established for applications that include in the treatment of anemias and hemorrhagic trauma. Red blood cells can be stored for up to 42 days under current AABB guidelines at reduced temperatures as detailed by Menitove, J. eds (1999) Standards for blood banks and transfusion services, 19th ed. Bethesda, Md: AABB. Technologies have been developed for the cryopreservation of RBCs for long-term storage in the frozen state that require post-thawing steps to remove the RBCs from cryopreservatives before infusion (Vengelen-Tyler, V. eds. (1999) AABB Technical Manual, p. 178 13th ed. Bethesda, Md: AABB). In order to minimize the logistical complexities of blood banking fresh and cryopreserved RBCs, we have developed methods for preparing lyophilized RBCs with a prolonged shelf-life for infusion after simple rehydration with H2O or buffer.
Two methods have been described previously for the preparation of lyophilized RBCs. First, Goodrich et al. (Proc. Natl. Acad. Sci. USA (1992) 89, 967-971; U.S. Pat. No. 4,874,690) outline methods for freezing RBCs in the presence of monosaccharides, polyanions and polymers and drying by sublimation of water. Post-hydration processing is required to remove the cryopreserving agents. Secondly, Bakaltcheva et al. (2000) Cryobiology 40, 343-359 describe procedures for stabilizing RBCs with the reversible chemical cross-linker dimethyl 3,3-dithiobispropionimidate and then freezing the cells in the presence of glucose as a cryopreservative with hemoglobin ligated by carbon monoxide. After freeze-drying and lyophilization, the cells are rehydrated and the cross-linker is reversed with dithioerythritol to restore approximately native osmotic fragility and deformability.